<template>
    <div class="app-container">
      <!-- 课程信息表单 -->
      <el-form label-width="120px">
        <el-form-item label="课程标题">
          <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"/>
        </el-form-item>
        <!-- 课程讲师 -->
        <el-form-item label="课程讲师">
          <el-select
            v-model="courseInfo.teacherId"
            placeholder="请选择">
            <el-option
              v-for="teacher in teacherList"
              :key="teacher.id"
              :label="teacher.name"
              :value="teacher.id"/>
          </el-select>
        </el-form-item>
        <!-- 所属分类：级联下拉列表 -->
        <el-form-item label="课程类别">
          <!-- 一级分类 -->
          <el-select
            v-model="courseInfo.subjectParentId"
            placeholder="请选择"
            @change="subjectChanged">
            <el-option
              v-for="subject in subjectList"
              :key="subject.id"
              :label="subject.title"
              :value="subject.id"/>
          </el-select>
          <!-- 二级分类 -->
          <el-select v-model="courseInfo.subjectId" placeholder="请选择">
            <el-option
              v-for="subject in subjectLevelTwoList"
              :key="subject.id"
              :label="subject.title"
              :value="subject.id"/>
          </el-select>
        </el-form-item>
        <el-form-item label="总课时">
          <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="请填写课程的总课时数"/>
        </el-form-item>
        <!-- 课程简介-->
        <el-form-item label="课程简介">
          <el-input v-model="courseInfo.description" type="textarea" rows="5"/>
        </el-form-item>
        <!-- 课程封面 -->
        <el-form-item label="课程封面">
          <el-upload
            :show-file-list="false"
            :on-success="handleCoverSuccess"
            :before-upload="beforeCoverUpload"
            :on-error="handleCoverError"
            :action="BASE_API+'admin/vod/file/uploadFile'"
            class="cover-uploader">
            <img v-if="courseInfo.cover" :src="courseInfo.cover">
            <i v-else class="el-icon-plus avatar-uploader-icon"/>
          </el-upload>
        </el-form-item>
        <el-form-item label="课程价格">
          <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder="免费课程请设置为0元"/> 元
        </el-form-item>
      </el-form>
  ​
      <div style="text-align:center">
        <el-button :disabled="saveBtnDisabled" type="primary" @click="saveAndNext()">保存并下一步</el-button>
      </div>
    </div>
  </template>
  <script>
  import courseApi from '@/api/vod/course'
  import teacherApi from '@/api/vod/teacher'
  import subjectApi from '@/api/vod/subject'
  export default {
    data() {
      return {
        BASE_API: 'http://localhost:8300',
        saveBtnDisabled: false, // 按钮是否禁用
        courseInfo: {// 表单数据
          price: 0,
          lessonNum: 0,
          // 以下解决表单数据不全时insert语句非空校验
          teacherId: '',
          subjectId: '',
          subjectParentId: '',
          cover: '',
          description: ''
        },
        teacherList: [], // 讲师列表
        subjectList: [], // 一级分类列表
        subjectLevelTwoList: []// 二级分类列表
      }
    },
    created() {
      if (this.$parent.courseId) { // 回显
      this.fetchCourseInfoById(this.$parent.courseId)
       } else { // 新增
      // 初始化分类列表
        this.initSubjectList()
        }
       // 获取讲师列表
        this.initTeacherList()
    },
    methods: {
        // 获取课程信息
    fetchCourseInfoById(id) {
      courseApi.getCourseInfoById(id).then(response => {
        this.courseInfo = response.data
        // 初始化分类列表
        subjectApi.getChildList(0).then(response => {
          this.subjectList = response.data
          // 填充二级菜单：遍历一级菜单列表，
          this.subjectList.forEach(subject => {
            // 找到和courseInfo.subjectParentId一致的父类别记录
            if (subject.id === this.courseInfo.subjectParentId) {
              // 拿到当前类别下的子类别列表，将子类别列表填入二级下拉菜单列表
              subjectApi.getChildList(subject.id).then(response => {
                this.subjectLevelTwoList = response.data
              })
            }
          })
        })
      })
    },
    // 保存并下一步
    saveAndNext() {
      this.saveBtnDisabled = true
      if (!this.$parent.courseId) {
        this.saveData()
      } else {
        this.updateData()
      }
    },
    // 修改
    updateData() {
      courseApi.updateCourseInfoById(this.courseInfo).then(response => {
        this.$message.success(response.message)
        this.$parent.courseId = response.data // 获取courseId
        this.$parent.active = 1 // 下一步
      })
    },
      // 获取讲师列表
      initTeacherList() {
        teacherApi.list().then(response => {
          this.teacherList = response.data
        })
      },
      // 初始化分类列表
      initSubjectList() {
        subjectApi.getChildList(0).then(response => {
          this.subjectList = response.data
        })
      },
      // 选择一级分类，切换二级分类
      subjectChanged(value) {
        subjectApi.getChildList(value).then(response => {
          this.courseInfo.subjectId = ''
          this.subjectLevelTwoList = response.data
        })
      },

      // 上传成功回调
      handleCoverSuccess(res, file) {
        this.courseInfo.cover = res.data
      },

      // 上传校验
      beforeCoverUpload(file) {
        const isJPG = file.type === 'image/jpeg'
        const isLt2M = file.size / 1024 / 1024 < 2

        if (!isJPG) {
          this.$message.error('上传头像图片只能是 JPG 格式!')
        }
        if (!isLt2M) {
          this.$message.error('上传头像图片大小不能超过 2MB!')
        }
        return isJPG && isLt2M
      },

      // 错误处理
      handleCoverError() {
        console.log('error')
        this.$message.error('上传失败2')
      },

      // 保存
      saveData() {
        courseApi.saveCourseInfo(this.courseInfo).then(response => {
          this.$message.success(response.message)
          this.$parent.courseId = response.data // 获取courseId
          this.$parent.active = 1 // 下一步
        })
      }
    }
  }
  </script>
  <style scoped>
  .tinymce-container {
    position: relative;
    line-height: normal;
  }
  .cover-uploader .avatar-uploader-icon {
    border: 1px dashed #d9d9d9;
    border-radius: 6px;
    cursor: pointer;
    position: relative;
    overflow: hidden;
    font-size: 28px;
    color: #8c939d;
    width: 640px;
    height: 357px;
    line-height: 357px;
    text-align: center;
  }
  .cover-uploader .avatar-uploader-icon:hover {
    border-color: #409EFF;
  }
  .cover-uploader img {
    width: 640px;
    height: 357px;
    display: block;
  }
  </style>